Balloon-envelope material and process of manufacturing the same



Dec. 29 1925 :1 ;56 7; i

E. TRENCKMA'NN' ET'AL BALLOON ENVELOPE ATERIAL AND PROCESS 'OFUMANUFAGTURING THE SAME Filed Aug st-27 1921 Patented Dec. 29, 192 5.

*FUNITED STA'TES.

1,567,556 PATENT OFFICE.

' Enron TRENCKMANN AND ammo rrmncxmann, or 'BERLIN-TIEMPELHOF, GER- MANY, v.assrauons TO B. e. TEXTILWERKE e. m. ,B. 11., or BERLIN-TEMPELHOF,

GERMANY. Y

' P I BALLOON-ENVELOPE MATERIAL AND PROCESS OF MANUFACTURING THE SAME.

' Application filed August 2?, 192 1. Sci-lag No. 495,934.

* eaim'nn UNDER THE raovrsrons or Erna ACT or masons, 1921, 41 STAT. I.., 1313.

i 1 the following is a specification.

Our invention refers to balloon envelope material-and its particular object is to effect a saving. in the materials hitherto in use for this pur ose without sacrificing. any advantages o ered by these materials.

' As is well known to those skilled in the art, the materialused up to date in the manufacture of balloon envelopes consisted either 'of waterproofed cloth or of gold heaters skin or thelike. Rubbered material involved the drawback of being too heavy in weight. On the other hand animal products, 's'ucl1-.- as goldbeaters skin, were too sensitive against friction, too little resistive '30 'to'ripping and not sufiiciently gas-tight. For. all these reasons animal products, suchas skins and intestines have to be employed in a number of'superposed layers, this way ofproceeding, however, leading to an enormous consumption of material. so that it proved impossible to satisfy the demand. It isclear that a great saving in valuable v material could b fi'ected, if it were'possible to improve the animal or vegetable material 40 or both, which have been used up till now, in such a manner as to, render them practically gastiglht without materiallyincreasing their weig t and without impalring their elasticity and mechanical'power of resis- .45.tanee..; v.)

I V have now ascertained that by combming the materials used up till now, animal as-well-as vegetable,- with a mixture described and claimed in our co-pending 'ap- .50.-plication for patent of the United States filed August 27, 1921, Serial No. 195,93 5,

, said mass substantially consisting of a mixture of a substance having the principal characteristics of glue and a substance adapted to impartto it elasticity. The properties of the fabric as well as gold- ,beaters skin or other vegetable-or animal material used in the manufactureof balloon envelopes are so greatly improved that the number of layers required for the envelope can be greatly reduced so that a great part of the material is saved. Our inventiontherefore'consists in a fabric to be used in combination with goldbeaters skin or some other suitable animal product of a similar character, such fabric being treated with a mixture in such a manner that the mixture acts as a means for impregnating the fabric so as to-render it gastight and as an agglutinant for. uniting the layers of fabric and goldbeaters" skin or the like.

The-figure of the drawing illustrates a sectional view 'of a portion of the material ofthis invention. V

In the case where it is desired to combine fabric with goldbeaters skin or some other animal product of similar properties, we prefer proceeding as follows: The animal product such as goldbeaters skin having been prepared by gluing a number of single skins together so as to form a number of superposed layers which are then dried, is moistened by means of a wet rag and then stretched on a table orframe. This treatment is 1 designed to cause a, preliminary elongation of the skin which is however prevented from contracting, while drying, beyond its original size owing to the fact that it is fixed on all four sides. Thus a drawback isobviated which generally presented itself whenever a fabric was united with the skin, the agglutinant used for this purpose causing the skin, to elongate considerably,

such elongation being however followed by a contraction which caused the layers --of fabric and skin to separate as soon as the compound material was subjected to any stress or pressure. This 1s successfully avoided by the treatment described above which may then be followed by the application of the fabric, the agglutinant having been in the meantimeapphed by. means of a brush to the skin. Preferably pressure is applied to the fabric by a squeeze-roller. In order to render the products thus obtained waterproof, their inner and outer surfaces preferably receive a coating of a good balloon varnish. The agglutinant which we prefer to use is a mixture which is spread onthe fabric by'means of well known spreading appliances, such mlxture consisting of glue, preferably bone-glue or some material having the principal characteristics of glue, such as isinglass, casein or gelatine, and a substance or substances adapted to render the glue as well as the fabric, to which it is applied, elastic, amongst such substances being oils, either soluble. or insoluble, in water, further insoluble fatty acids, glycerine and the like. The

preferred mixture consists of 100 parts water, 10 parts gelatine, 1O parts Turkey red oil,.or turcon oil, this being a substitute for the former, and'five parts glycerine, 0.25 part bi-chromate of potash or formaldehyde being added, if desired, in order to .render the mixture highly waterproof.

In the compound material thus obtained the fabric serves for compensating the low resistance to ripping and the general sensitiveness of the animal products, while the' layers of goldbeaters skin or the like may be only very few inasmuch as the novel mass notonly acts as an agglutinant holding the different layers and materials together but also serves as an impregnating means filling the pores of the fabric and rendering it absolutely gastight.

Apparently all these conditions can be fulfilled only by a mass which is at the same time highly adhesive, light and absolutely gastight. Moreover as goldbeaters skin elongates about less than the fabric combined therewith the elasticity of the agglutinant must be such thatron the balloon envelope being subjected to a tensile stress the difference of elongation is compensated and a splitting off of layers is avoided. Rubber solution cannot be used on account of its insulating qualities. On the otherhand vegetable agglutinants are not sufficiently adhesive and the dextrines which are usually employed are too brittle and, if greater quantities of glycerine are added, become hygroscopic and therefore unfit for use with balloon envelope material.

neonate We claim 1. The process for maklng balloon envelope material WlllCh' consists in molstenmg a sheet of one or more layers of animal provenience, stretching same, applying a mixture of a substance having the principal characteristics of glue and a substance adapted to render glue elastic, placing a sheet of fabric thereon and applying pressure.

2. The'herein described method of manufacturing fabric for the gas bags of airships or balloons which consists in proofing the fabric with a material having the principal characteristic of glue and a material adapted to render glue elastic, and apply- 5. A balloon envelope material as characterized in claim 4, further characterized by the fact that it comprises a layer of varnish on the goldbeaters skin.

6. The process for making balloon envelope material which consists in moistening a sheet of one or more layers of animal pro:

venience, stretching same, applyinga mixture of a substance having the principal characteristics of glue. and 'a substance adapted to render glue elastic, and placing a sheet of fabric thereon and applying pressure and then applying a coating of varnish thereto.

7;" Ihe process for making balloon envelope material which consists in stretching. a sheet of one or more layers of animal provenience, applying a mixture of a substance having the principal characteristics of glue and a substance adapted to render glue elastic, and placinga sheet of fabric thereon and applying pressure. In testimony whereof we hereunto afiix our signatures.

- ERIGH TRENOKMANN. BRUNO TRENCKMANN. 

